HR: 1330h
AN: H42D-1107 INVITED     [PDF]
TI: Hydraulic Property Upscaling in heterogeneous Soils
AU: * Mohanty, B P
EM: bmohanty@tamu.edu
AF: Texas A&M University, 2117 TAMU Biological and Agricultural Engineering, College Station, TX 77843 United States
AU: Zhu, J
EM: jzhu@cora.tamu.edu
AF: Texas A&M University, 2117 TAMU Biological and Agricultural Engineering, College Station, TX 77843 United States
AB: We discuss two themes for upscaling of soil hydraulic properties in both steady state and transient flows in heterogeneous soils: (1) hydraulic parameter averaging schemes in describing the ensemble behavior of heterogeneous formations and, (2) the effective hydraulic parameters obtained by conceptualizing the heterogeneous soil formation as an equivalent homogeneous medium that will approximately discharge same flux as the ensemble flux of the heterogeneous formations. For the steady state flows, we compare the averaging schemes and the ensemble behavior of the heterogeneous soils and address their effectiveness and uncertainties. We also investigate the impact of parameter correlation, boundary condition (surface pressure head) and elevation above water table on the effective hydraulic parameters. For the transient flows, we investigate the effective soil scaling factor for infiltration under relatively wet conditions in terms of the optimal effective powers for the input parameter fields. The derived optimal effective powers for the random parameters define an optimal averaging scheme for the random fields. Specifically, we discuss the effects of microtopography (as reflected in surface ponding depth), and hydraulic parameter correlation on the ensemble behavior as well as on the optimal effective powers. Variability of the Miller-Miller scaling factor has the most significant effect on the ensemble flux behavior. The correlation among the Miller-Miller scaling factor, the saturated water content and the surface ponding surface increases the effects of soil heterogeneity. However, the ensemble flux behavior can be more precisely mimicked through the idea of optimal effective powers when the random fields are better correlated.
DE: 1824 Geomorphology (1625)
DE: 1833 Hydroclimatology
DE: 1866 Soil moisture
DE: 1869 Stochastic processes
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2003 Fall Meeting